The invention relates to compounds of formula I ##STR2## in which X, Y, R(1), R(2), R(3), R(4), R(5) and R(6) have the meanings indicated, their preparation and use, in particular as pharmaceuticals. The compounds affect the potassium channel opened by cyclic adenosine monophosphate (cAMP) or the I.sub.Ks channel and are outstandingly suitable as pharmacentically active compounds, for example for the prophylaxis and therapy of cardiovascular disorders, in particular arrhythmias, or for the treatment of ulcers of the gastrointestinal region or diarrheal illnesses.
In recent years in the field of pharmaceutical chemistry, the 4-acylaminochroman derivative class has been studied, and a few corresponding chromene derivatives have also been described. The most prominent representative of this class is cromakalim of formula A, and an example of the corresponding chromene is the compound of formula B (J. Chem. Soc. Perkin Trans. 1, 1991, 63-70). ##STR3## Cromakalim and other related 4-acylaminochroman derivatives are compounds which have a relaxant activity on smooth muscular organs. Thus, they are useful for lowering raised blood pressure as a result of vascular muscle relaxation and in the treatment of asthma as a result of the relaxation of the smooth musculature of the lungs. It is common to all these preparations that they act at the cellular level of smooth muscle cells and cause an opening of specific ATP-sensitive K.sup.+ channels of these cells. This increase in the negative charge in the cell (hyperpolarization) induced by the efflux of K.sup.+ ions counteracts via secondary mechanisms the increase in intracellular Ca.sup.2+ concentration which leads to cell activation and which, in turn, leads to muscle contraction.